Hödur was
hunting in Járnviður (Iron-Wood) and stayed overnight in a cave,
where a witch welcomed him, and bewitched him with a magical potion, so that
he was tricked into swearing an oath to gain the love of Nanna, Baldur's betrothed.

The magical
potion filled Hödur's heart with a burning love for his brother's fiancée.

When he woke
up the next morning he was filled with shame, but nevertheless he was bound
by his oath to betray his brother.